1. Field of the Invention
The invention relates to a security tag and to an unlocking device for releasing the fastening parts of the security tag.
2. Discussion of the Background
Security tags which trigger an audible signal, are known for example when leaving shop premises, if the object which is protected thereby is taken through a barrier which operates without contact. Such a barrier can, for example, have an induction loop with an oscillator and the security tag can have an inductor which causes a resonance. Such means for triggering a signal are, however, not the subject of the present invention and are assumed to be known, so that the said means are not described in detail here.
A security tag of the type mentioned initially, disclosed in EP-Al 0,405,155, can be opened on a mechanical or magnetic basis. Although special devices are provided for opening, it is not inconceivable that such security tags can be opened even without such devices by way of other means, for example magnets, and the goods protected thereby can be stolen.